India Receives Fourth S-400 Air Defence System

India is set to receive the fourth squadron of the Russian-origin S-400 air defence missile system by the end of the week of 19 May 2026. The system forms part of a $5.43 billion agreement signed in 2018 for five S-400 squadrons from Russia.

S-400 Missile System

The S-400 Triumf is a long-range surface-to-air missile system developed by Russia. It is designed to engage aircraft, cruise missiles, and ballistic missiles at different ranges and altitudes. The system is operated by the Indian Air Force for air defence deployment.

India-Russia Defence Contract

India signed the contract for five S-400 systems in 2018. The original delivery schedule aimed for completion by 2023, but the timeline faced delays linked to the Russia-Ukraine conflict and disruptions in Russian defence supply chains. The fourth unit was inspected by Indian Air Force personnel in Russia by mid-April 2026 and was shipped by sea and air transport.

Deployment and Procurement Plans

The fourth S-400 unit is expected to be deployed in Rajasthan for long-range air defence coverage along the western frontier. The fifth and final squadron under the original contract is expected by November 2026 and is likely to be positioned along India’s northern border with China. In late March 2026, the Defence Acquisition Council approved a new batch of five additional S-400 missile systems.

Important Facts for Exams

• The S-400 Triumf is a Russian-made long-range surface-to-air missile system.
• India signed a $5.43 billion contract in 2018 for five S-400 squadrons.
• The Indian Air Force uses the S-400 for air defence against aircraft, cruise missiles, and ballistic missiles.
• The Defence Acquisition Council is the apex body for capital procurement decisions in the Ministry of Defence.

Missile Inventory and Associated Procurement

India has also decided to purchase 288 anti-aircraft missiles for the S-400 system, including 120 short-range missiles and 168 long-range missiles. The estimated cost of this missile replenishment package is about $1.2 billion.

Operational Use

The S-400 systems have reportedly been used by the Indian Air Force during Operation Sindoor in May 2025. The planned additional procurement could raise India’s total S-400 inventory to ten squadrons.